Dubowitz Syndrome

Genetic disorder with craniofacial (craniosynostosis), neurologic, orthopedic and dermatologic anomalies.

Approximately 150 cases have been reported in the literature since the first description of the syndrome by V. Dubowitz in 1965.

Autosomal recessive.

The precise mechanisms leading to the very wide phenotypic presentations of the syndrome remain to be determined.

No biochemical characterization to confirm Dubowitz syndrome is available. Diagnosis is based on clinical features (mainly facial appearance), which show a high variability and may result in underdiagnosis of the disorder.

Very high variety of combinations of multiple anomalies may be present, which is at least in part responsible for the difficulties in confirming the diagnosis. Intrauterine and postnatal growth retardation and delayed osseous maturation lead to (proportionate) short stature in approximately 80% of patients. Mental retardation ranges from mild (common) to severe (rare), but average intelligence has been reported. Patients are often described as hyperactive with a short attention span (67%), stubborn, and shy. Muscular hypotonia is common (40%). Seizures are rare. Craniofacial anomalies may include microcephaly (with head circumference below the third percentile), premature craniosynostosis, distinctive, small face with high forehead, flat supraorbital ridge, short palpebral fissures, scanty or absent lateral part of the eyebrows, lateral telecanthus, hypertelorism, epicanthal folds, ptosis, blepharophimosis, and other ocular anomalies (e.g., strabismus, microphthalmia, iris hypoplasia, coloboma, and ocular albinism). The nasal tip is broad, and the ears are prominent or dysplastic. Micrognathia (may be severe) and retrognathia (rare), submucous cleft palate (44%), occasional velopharyngeal insufficiency, multiple dental problems (delayed eruption, missing teeth, extensive caries), and a high-pitched and hoarse voice (68%) have been described. Cardiovascular anomalies are rare but can occur in the form of coarctation of the aorta, aberrant subclavian artery (dysphagia lusoria), occlusion of the internal carotid artery, persistent ductus arteriosus, ventricular septal defect, and mitral valve prolapse. Patients often suffer from eczema (58%), which tends to improve with age; sparse hair; and pilonidal dimples. Brachyclinodactyly of the fifth finger is a constant feature, the joints are hyperextensible, and, patients occasionally present with scoliosis or spina bifida occulta. Genital abnormalities, such as cryptorchidism, hypospadias, and inguinal hernia, are common. Gastroesophageal reflux disease, vomiting, chronic diarrhea, or chronic obstipation may be present. Bone marrow hypoplasia may occur in up to 6% of patients, and case reports of fatal aplastic anemia exist. On the one hand, patients have increased susceptibility to recurrent infections (of upper airway, ears, and urinary tract, most likely secondary to IgA, IgG, and/or IgM deficiencies) and malignancies (leukemia, lymphoma, neuroblastoma, rhabdomyosarcoma). On the other hand, allergies are very frequent findings.

Obtain a full medical history and clinical assessment of the airway and the degree of muscular hypotonia. Request a pulmonary function test if any doubt about respiratory compromise exists. Ask about previous anesthesias and any related complications. Blood examination should include a complete blood count and a hemoglobin level (because of possible bone marrow hypoplasia, immunodeficiency). Check electrolyte levels (hypoparathyroidism has been described). In the rare case of seizure disorder, inquire about anticonvulsant therapy, and its efficacy and toxicity. Depending on the degree of mental retardation, sedative and anxiolytic premedication and the presence of the primary caregiver during induction may be helpful.

Micrognathia and submucous cleft rarely make tracheal intubation difficult. In the presence of retrognathia (infrequent) or any type of anticipated difficult airway, spontaneous respiration should be maintained while securing the airway by fiberoptic intubation. In cases of gastroesophageal reflux or recurrent vomiting, a rapid-sequence intubation is recommended. However, keep in mind that almost half of patients show signs of muscular hypotonia. Correction of anemia and thrombocytopenia may be necessary in cases of bone marrow hypoplasia, and good vascular access is recommended. Allergies are frequent, and the anesthetist should be prepared to treat them should they occur.

Succinylcholine is contraindicated because of the risk of hyperkalemia. Nondepolarizing muscle relaxants are often unnecessary or should be titrated under the control of a peripheral nerve stimulator because increased sensitivity has been reported. If a seizure disorder is present, potentially epileptogenic drugs (methohexital, ketamine, enflurane, meperidine, atracurium, and cis-atracurium) should be avoided. Some antiseizure drugs induce the hepatic enzyme system, which may result in altered metabolism of predominantly hepatically eliminated drugs. Subacute bacterial endocarditis prophylaxis may be required, depending on the presence of cardiac lesions and the kind of procedure.